Improvement in knob-latches



H. H. ELWELL.

KNOB LATCHES.

' Nb.174,504. Pat ente'd March 7,1876;

1714/ rm/ 4? L/ fl/M/ML W fi UNITED. STATES PATENT. QFFEGE,

HENRY H. ELWELL, on NORWALK, comm, ASSIGNOR TO THE NORWALK LOOK,COMPANY, OF SAME 'PLAOE.

|MPROVEMENT* IN KNOB-LATCHES.

Specification forming part of Letters Patent N 0. 174,504, dated March7, 1876; application filed February 21, 1876, I

To all whom it may concern: Be it known that I, HENRY H. ELWELL, 0Norwalk, in the county of Fairficld and State of Connecticut, haveinvented a new [mprovement in Knob-Latches; and I do hereby declare thefollowing, when taken in connection with the accompanying drawings, andthe letters of reference marked thereon, to be a full, clear, and exactdescription of the same, and which said drawings constitute part of thisspecification, and represent an interior View of a latchembodyingthisilnprovement.

This invention relates to an improvement in knob-latches, the objectbeing to lock the latch-bolt on one side of the door, so as to preventits movement through the knob on the other, and to take advantage of thespring which throws the bolt, causing it to serve the double purpose ofthrowing the bolt and hold ing the lock; and it consists in a cam-leverwithin the case, so that by turning the said lever it com es'intoposition against the shoulder in the unlocked position by means of anextension of the spring collar, as more fnlly hereinafter described.

A is the latch-bolt; B, the follower; G, the spring; a, the collar, thespindle passing through the collar a, the said collar serving as abearin g for the spring in the usual manner. I1 is the locking-lever,arranged upon abearing in the case, and so as to be turned The other end0 forms a cam for the action of the spring. In the usual construction anindependent spring has been applied to hold this locking-lever in eitherof its two positions.

To dispense with this spring, the collar to is extended to form an arm,d, bearing against the can) 0, and .bent so as to form oppositeinclines, one of which will bear upon the under side of the cam in itsunlocked position, and the other upon the reverse side in its lockedposition; hence, in turning the cam, the collar extension Will be thrownback out of its plane, as indicated in broken lines, its fit on thespindle being sufficiently loose -to allow this play. The latch-boltspring, bearin g upon the front of the collar, tends at all times toforce this extension against the cam 0, thus serving a double purpose,and dispensing with the additional spring usually required. ot' thelatch-bolt, and its cam held in that or i I claim- In combination with alatch-bolt, its spring and the locking cam-lever c b, the collar a, withits extension at to bear against the cam a, substantially as described.

HENRY H. ELWELL. Witnesses:

WILLIAM T. BONTON, ALBERT F. MINTON.

